Five children were killed or wounded by gunfire in the US state of Texas over the weekend, including a 4-year-old boy who was shot dead by his five-year-old brother, according to police and US media reports.

The bloodshed showed once again the dangers of firearms in the United States, where 30 percent of adults say they own at least one gun.

The incident involving the two brothers occurred Sunday in Fort Worth, Texas where police told AFP the older boy found a gun in his home and fired the shot that killed his little brother.

"At this time, there will be no charges filed," police spokesperson Jimmy Pollozani said in an email.

Several hours later, a six-year-old boy was seriously wounded in nearby Arlington, Texas, by a bullet probably fired by one of his brothers.

Several children were playing in a bedroom when a boy aged about 10 found a rifle, pointed it and pulled the trigger, Christopher Cook of the Arlington police told the Dallas Morning News.

The six-year-old was in critical condition with a head wound. A three-year-old girl also was lightly wounded, the newspaper said.

An adolescent who was present told police the rifle belonged to him. His parents denied any knowledge of the weapon and investigators have yet to determine how he obtained it.

Sunday evening, an eight-year-old girl was wounded by a shot from a stolen semi-automatic weapon, the Morning News reported.

Her parents said the girl was sitting on the gun when it went off. Police are investigating the circumstances.

In a yet another incident Sunday, a 14-year-old girl was admitted to a Fort Worth hospital with a gunshot wound, CBS News reported. The circumstances surrounding that shooting were not immediately known.